Fuel pump



March 5, 1946. N. FoDoR 2,395,964

, FUEL PUMP Filed Nov. 19, 1942 3 Sheets-Sheet 1 mum` 1 l l d4 A 4 N. FDOR FUEL PUMP March 5,l 1946.

5 Sheets-Sheet 2 vFiled Nov. 19, 1942 I INVENTORQ JVC/zolaodofr BY March 5, 194e.

N FoDoR FUEL PUMP Filed Nov. 19. 1942 7 5 sheets-sheet s 1N VEN TOR. l

' the invention and lthe scope of the appended y held in position by theA coupling members 39,

of generally cylindrical form which is composed 35 known manner with the spaces above the tops Patented Mar. 19,46 I v v i .I

UNITED .STATES PATENT CHUCE l v y2,395,964 i Nicholas Fedor; Wiimette, m. Application November 19, 1942, Serial No.'466,093

' somme (c1. 12s-139) This invention has to do with fuel pumps for 28 which are vertically slidable in guideways 29 use with multi-cylinder engines, and is partic-` formed in the section I4. The cam followers 23 ularly concerned with fuel pumps vof the type are provided with screw tappets 30towhich access adapted to deliver Diesel fuel under high presmay be had for adjustment through suitablycovsure to the injectorsy in the cylinders of Diesel 5 ered side openings 3i in the section I4. The engines. l y plungers 26 are provided with return springs 32 The principal object of the invention is to prowhich are compressed between the under surface vide an improved pumping unitv of the type deof the section I3 and thrust washers 33 on the A scribed in which thech'arges of fuel delivered by vlower headed ends of the plungers. The cam the unit may be easily and accurately controlled. l0 followers 28 are provided at their lower ends with While the foregoing statement is indicative in anti-friction rollers 34. l a general way of the nature of the invention, V The barrels 23 are closed off at their upper other more specific objects and advantages will ends by circular valve plates 35 which contain be apparent to those skilled in the art upon a full discharge ports 36, and the discharge ports 36 understanding of the construction, arrangement 15 are normally closed bydownwardly spring-pressed and operation of the improved pumping unit. valves 31 which are located within coupling mem- One embodiment of the invention is presented bers 38. The coupling members 38 are adapted herein` -for the purpose of exempliiication, but it. to be' connected by suitable piping (not shown) will of course be appreciated that the invention with the usual injectors in the cylinders of the may be incorporated in other structurally mod- 20, associated engine. The barrels y23, with their asified forms coming equally within the spirit of sociated valve plates 35, are clamped together and claims. which members are screwed into` the top II of l In the accompanying drawings: the housing. The barrels 23 are provided on the Fig. lisa reduced side view of the new pump- 25 sides thereof toward the center of the housing ing unit; with inlet ports 349, and are provided on the sides Fig. 2' is a plan view of the same; thereof away from the center of the housing with Fig. 3 is a vertical diametric section through spill ports 4u. Set screws 4I project laterally from the unit, taken on the line 3-3 of Fig. 2; the top section II 'into slots 42 in the outer sides Fig. 4 is ahorizontal section, taken on the line 3o of the barrels 23, whereby to position the barrels 4,-4 of Fig. 3; and with the ports 39- facing inwardly and the ports Fig. 5 isanother horizontal section, taken on 49 facing outwardly. The plungers 26 are prothe line 5-5 ofFig. 3. vided adjacent their upper ends with annular The pump unit includes an upright housing In grooves 43, which grooves communicate in a well of top, bottom and intermediate sections II, I2, I3 lof the plungers through passages 44. The inlet and I4. The several sections are fastened rigidly ports 39 on the inner sides of the barrels 23 all together by screws I5, and the bottom section I2 communicate with a centrally located fuel chamis provided with a mounting flange I6 which is ber 45 formed in the underside of the top secadapted to be secured to a portion Il of the crank 40 tion, While the spill ports l4I) in the outer sides case of the associated engine by screws I8. A of the barrels all communicate with an annular shaft I9 is journaled in the housing I0, coaxially passage 46 in the outer portion of the section II. of the latter, in upper and lower bearings 20 and The fuel which is to be pumped enters the cham- 2I, and a drive gear 22 is attached tothe lower ber 45 through an inlet 41. A relief valve 48 also end of the shaft I9 at a point adjacent the bot.- 45 communicates with the chamber 45. tom of the housing. A circular cam 49 is located within the lower A plurality of barrels 23 (one for each of the portion of the housing, within a cavity 50 formed cylinders of the multi-cylinder engine with which in the bottom section I2. The cam 49 is ar.. the unit is to be used) are seated in axially aligned ranged concentrically with respect to the shaft bores 24 and 25 formed in the top and upper in- 50 I9 and is connected for rotation with the latter termediate sections II and I3 of the housing I0. by means which will later be described, The The barrels 23 are arranged in a circle about the cam 49 is provided with an upwardly facing cir- Shaft I9, in equally spaced relation to each other, cular cam surface 5I, which surface underlies with their axes parallel to that of the shaft. The all of the cam followers 28 and engages with the barrels 23 contain 0105815' -tting Pumping lillmt'-v 55 anti-friction rollers 34 of the cam followers. ers 26. The lower ends ofthe plungers 26 project The dwell of the gil-cular cam surface 5| exfrom the lower ends of the barrels 23 into a relatends almost entirely about'the circumference of tively large cavity 21 formed' in the upper portion such surface, with the result that all of the inlet of the lower intermediate section I4. The lower ports 39, with the exception of preferably not ends of the plungers 26 engage with cam followers .60 more than one, are-shut of! at any given instant the cavity 50 and functions as a piston.

backing plate 53 is provided about its periphery view the inlet port 39 has just been uncovered by the side of the upper end of the plunger and the cam follower roller 34 has just left the dwell ofthe cam surface 5I and is about tostart up again on the lift leading to the dwell. Since the chargesof fuel can enter the barrels 23 only the reciprocating movement of the plungers 23 enters the barrels from the chamber 45 by way of the inlet ports 39. The flow of the 'fuel through the ports39 is progressively cut down during the very short period of time in which the cam follower rollers 34 are out of engagement with the dwell, and since the maximum rate of flow through the small inlet ports 39 is more or less determined by the size of such ports, any

tendency of the engine to speed up, for example, from the particular speed for which the engine has been manually set will be effectively counteracted by the decreased amount of fuel getting through the inlet. ports 39 during the shortened time period in which such ports are uncovered, and vice versa with respect to any tendency of the engine to slow down, with the result that the speed of rotation of theengine will tend to remain constant for any particular setting.

The cam 49. instead `of being ilxedly keyed to the shaft I9, is connected with the latter through a number of helical splines 52. The helical shape of the splines 52 acts to alter the angular position of the cam with respectto the shaft when the cam is either raised or lowered-any raising of the cam from the position shown'in Fig. 3 serving both to cut down the amount of fuel b eing pumped to the injectors and to retard the time at which the decreased amount of fuel is pumped.

The cam 49 is supported for rotation on a stationary backing plate 53, through an interposed thrust bearing 54. The plate 53 is secured to the upper surface of a piston-like member A55 by screws 56. The member 55 is provided with a downwardly extending tubular portion 51 which is exteriorly threaded for screw-threaded engagement with a correspondingly threaded portion 59 of the bottom section I2. The periphery of the member 55 is arranged in closely ttingbut vertically slidable engagement with the wall 5s if T e with teeth 60. which teeth at one side of the plate mesh with teeth 6I on a horizontally shiftable rack 52. The rack 62 is formed on a rod 63 which is supported in apertured bosses 64 and 65 projecting from the bottom section I2. A set l screw 66 extends from the boss -64 into a slot 61 in the back of the rackv 62, whereby to position the rack properly with respect to the backing plate 53.

To facilitate the raising of the backing plate 53 against the substantial pressure opposed to the same, the space 68 in the cavity 5U beneath the member 55 may be filled with oil under pressure from the engine-the oil entering the space 63 from an annular duct 69 which communicates at one -pointwith a duct 10 formed in the adjacent portion I1 -of the crank case. The pressure of this oil acts to counterbalance to a considerable extert the load on the backingv plate 53, thus permitting the backing plate to be screwed upwardly by the rack 62 with but little resistance.

A relief valve 1I may be provided in the bottom section I2 for the oil coniinedwithin the space ss.

As previously stated, the fuel which is pumped from the barrels 23 to the several injectors by upper intermediate section I3 above a predetermined maximum speed of the engine by a slide valve 12 in the chamber 45. The valve 12 is of generally circular form and is characterized by a peripheral skirt portion 13 which nts against the inwardly facing sides of` the barrels 23 in more or less overlapped relation to the ports 39. When the speed of the engine exceeds a predetermined maximum the valve 12 will move into its uppermost position. In the uppermost position (which position is vthe one shown in Fig. 3) the skirt portion 13 of the valve ,acts to cut off practically vall ilow of the fuel through the ports 39. Downward movement of the valve 12 from its uppermost position acts to progressively increase the effective size of the tured at 11 for equalization of pressure above and below the same, and is apertured at 18 for the passage of screws 19 employed to clamp the pf the housing to the top 'section II. A flexible diaphragm 80 of synthetic rubber or other suitable material is connected at its upper end to the valve 12 and at its lower end to the section I3 for sealing off the compartment 45 at the location of the aperture 15. v

.The valve 'l2 is automatically regulated by a pair of centrifugally operated governor weights 9| which are located in the cavity21 in the lower intermediate section H. The weights 8i are pivotally attached at'32 to opposite sides of a bracket 83 carried by the shaft I9, and are provided with cam fingers 84 which extend inwardly into engagement with the underside of a bearing washer 35 attached to the lower end of the tubular stem portion 'I4 of the valve 12. When the speed of rotation of the shaft I9 starts to exceed a predetermined maximum the weights 3l will move outwardly, raising the valve 12 and progressively re' stricting the flow of fuelthrough the ports 39. This upward movement of the valve 12 is opposed by the action of a coil-spring 36 which is compressed between a washer 31 overlying the bearing washer 85 and a washer 83 positioned against the underside of the upper intermediate section I3. The speed at which the valve 12 will come into action can be varied by selecting a coil spring which will present the desired amount of resistance to compression.-

'Ihe improved pumping unit, while especially designed for use with a radial engine, can of course be employed with engines in which the cylinders are not arranged radially.

The operation of the above described pumping unit is` in brief as follows: The fuel enters the chamber 45 through the inlet 41 and ows from the chamber 45 into the barrels 23 through the partially restricted inlet ports 39. Thefuel is then pumped by they plungers 26 under higher pressure from the barrelsA 23v through the dischargey ports 35, with the fuelin excess of the quantity required in each charge escaping from. thebarrels through the spill ports 43 by way of lowermost position of the plungers 25 (which position determines the quantity of fuel pumped before the groove 43 in .the plunger starts by- .passing the excess fuel through the spill port 40) is `varied uniformly and simultaneously for all of the plungers by shifting the rack 52 to either 'raise or lower the backing plate 53. Raising of this plate reduces the quantity of fuel pumped by each ofA the plungers, while lowering it in creases the quantity pumped. Thehelical spline connection 52 between th cam!! and the shaft I9, by changing the angular position of the cam relative to the shaft, retards the time of pumping when the quantity pumped is decreased and advances the time when the quantity-is increased.

v'I'he hydraulic counterbalance for the backing plate,l obtained by admitting oil under pressure to the underside of the piston-like support 55 for the backing plate, permits the cam 49 to be raised or lowered with but little eort. The centrifugally operated weights 8 I, by determining the e asomar the grooves 43 and returning to the supply. The i cam, i'uel inlets and outlets for the barrels, said plungers operating with strokes oi' fixed length to pump fuel received from the inlets into the outlets in amounts which vary according to the positions of the plungers relative to the barrels when the plungers are at the lower ends of their strokes, a' stationary thrust-plate in back of the cam, means for raising or lowering the plate,

- whereby to vary the position of the cam and the area of the inlet ports uncovered by the plungers,' and thereby change the amount of fuel pumped from each barrel, and means controlled by the speed of rotation of the shaft for automatically metering the fuel entering the barrelsv through the inlets, said means consisting of a dwell on the cam which'extends about the greaterpart of the circumference of the latter, whereby i to allow the plungers to uncover their associated position of the slide valve 12 in conformity with a predetermined maximum speed of the engine, prevents the speed from becoming excessive.

I claim:

1. Inl a fuel pump for multi-cylinder engines, a shaft, means for rotating the shaft, a circular cam associated `with the shaft for rotation with the latter, a plurality of 'barrels arranged in a circle, about the shaft in frontof the cam, plungers in the barrels operatively associated with the cam, fuel inlets and. outlets for the barrels, Said plungers operating with strokes of fixed length to pump fuel received from the inlets into the outlets in amounts which vary according to the positions of the plungers relative to the barrels i when the plungers are at the lower ends of their strokes, a stationary thrust plate in .back of the cam, means for raising or lowering the plate,

the latter, a plurality of barrels arranged in a circle about the shaft in front of the cam, plungers in the barrels operatively associated with the cam, fuel inlets and outlets for the barrels; saidV plungers operating with -strokes of fixed length to pump fuel-received from the inlets into the outlets in amounts which vary according to the positions of the plungers relative to the barrels when the plungers are at the lower ends of their strokes, a stationary thrust plate in back of the cam, `means for raising or lowering the plate whereby to vary the position of the Acam and change the amount of fuel pumped from each barrel, and means controlledby the speed of rotation of the shaft for automatically metering the fuel entering the barrels through the inlets.

3'. In a fuel pump for multi-cylinder engines, a shaft, means for rotating the shaft, a circular cam associated with the shaft for rotation withthe latter, al plurality of barrels arranged in a circle albout the shaft in front of the cam, plunginlets for but a relatively shortperiod of time during each revolution of the cam, thus reducing the amount of fuel passing through the inlets upon an increase in the speed of rotation.

4. In a fuel pump for multi-cylinder engines, a shaft, means for rotating the shaft, a circular cam associated with the shaft for rotation with the latter, a plurality of barrels arranged in a e circle about the shaft in front ofthe cam, plungers in the barrels operatively associated with the cam, fuel inlets and outlets for the barrels, said plungers operating with strokes of fixed length to pump fuel received from the inlets into the outlets in amounts which vary according to the positions of the plungers relative to the barrels when the plungers are at the lower ends of their strokes, a stationary thrust plate in back of the cam, means for raising or lowering the plate, whereby to vary the position of the cam and change the amount of fuel pumped from each fbarrel, and means for automatically modifying the angular position of the cam with respect to the shaft when the plate is raised or lowered,

`whereby to alter the time when the fuel is pumped from said barrel, said last mentioned means'consisting of a helical spline connection between the cam and the shaft.

5. In a fuel pump for multi-cylinder engines, a shaft, means for rotating the shaft, a circular cam associated with the shaft for rotation with the latter, a plurality of barrels arranged in a circle about the shaft in front of the cam, plungers in the barrels operatively associated with the cam, fuel inlets and outlets for the barrels, said plungers operating with strokes of fixed length to pump fuel received from the inlets into the outlets in amounts which vary according to the positions of the plungers relative to the barrels when the plungers are at the lower ends of their strokes, a stationary thrust plate in' back of the cam,- means for raising or lowering the plate, whereby to vary the position of the cam and change the amount of fuel pumped from each barrel, and means controlled by the speed of rotation of the shaft for cutting down the rate of flow of the fuel entering the barrels through the inlets when the speed oiv rotation exceeds a predetermined amount, said last'mentioned means comprising a centrally arranged slide valve having portions thereof arranged inoverlapped reers in the barrels operatively associated with the lation to the inlets for the barrels, and a centrifugal governor for actuating the slide valve to increase the extend of overlap when the speed becomes excessive.

NICHOLAS FODOR.

Certificate of Correction Patent No. 2,395,964. Merch 5, 1,946. NICHOLAS FODOR It is hereby certied that errors appear in the rinted specification of the above numbered patent requiring correction as follows: age 2, second column, line 71, for higher read high; page 3, second column, line 43, claim 4, for "said barre read each'barrel; line 71, claim 5, for extend read extent; and that the said Letters Patent should, be read with these corrections therein that the same may conform to the record of the case in the Patent Oice. Y

Signed and sealed this-28th day of May, A. D. 1946.

[sum1 LESL'E FRAZEB,

First Assistant Commissioner of PuntualeL 

